1. Field of the Invention
The present invention broadly relates to the field of telecommunications, and more specifically to telephone networks, particularly fixed (wired) telephone networks.
2. Description of the Related Art
Wired telephone networks (also referred to as PSTN—Public Switched Telephone Networks) comprise, in their “last mile loop” that reaches the end users (subscribers of the telephony operator), distribution cabinets where the twisted pairs that lead to the subscribers' premises are attached to the cables that reach the telephone network core apparatuses, like for example the switching centrals.
These distribution cabinets are typically located along the streets pathways, in correspondence of the buildings where the subscribers' premises (e.g., apartments, offices) are located, or in the buildings' basements.
A distribution cabinet allows the connection of several different subscribers' twisted pairs, e.g. in a number of 10. In a typical PSTN, several hundred thousands of such distribution cabinets are necessary to bring the telephony services to the subscribers.
Testing and maintenance operations need to be periodically performed by qualified technicians of the network operator, for example in order to fix any possible malfunctioning reported by the subscribers. These operations often involve the distribution cabinets, which have to be accessed by the technicians to perform tests and controls on the different twisted pairs.
Accession to the distribution cabinets is also required for assessing which subscriber lines have already been assigned to subscribers, and which lines are instead free, for the identification (e.g., in terms of telephone number) of the different subscriber lines available in the generic distribution cabinet, for assessing the nature of the different telephone lines available in the distribution cabinet (e.g., plain old telephone line, ISDN—Integrated Service Digital Network—line, ADSL—Asymmetric Digital Subscriber Line). The information derivable from the field by the technicians are quite important to allow the telephony operator build and keep constantly updated a databank which provides a reliable view of the current telephone network status.
A consolidated practice adopted by the technicians for performing tests on the subscriber lines available in a distribution cabinet provides for them calling a colleague at a central of the telephone network using a selected one of the lines reaching the cabinet, and asking him/her to report the CLI (Calling Line Identity) associated with that line.
In WO 97/10666 a centralized test apparatus is provided for a telecommunications network which includes local switches and a core network. Each local switch is connected through terminating lines to terminating equipment such as telephone handsets. The test apparatus forms a centralized test apparatus for the whole network, and is implemented as a computer. The test apparatus enables a field engineer to obtain the identity of a terminating line from one of the local switches. When a field engineer dials the number of the test apparatus, the test apparatus retrieves the CLI on answering the call. It then transmits the CLI in speech form back to the calling line. After transmitting the CLI, the test apparatus offers a menu of further services which comprise a ring back service and the provision of a test tone on a specified telephone line.
In WO 98/47273, a similar centralized test apparatus is provided. The test apparatus is connected to the centralized database which contains routing tables for terminating lines of the access networks of the public telecommunications network. The test apparatus enables a field engineer to record routing data in the centralized database. When a field engineer connects a telephone instrument to a terminating line in a node in an access network, the engineer can dial the number of the test apparatus. The test apparatus retrieves the CLI on answering the call. It then invites the field engineer to enter an identifier for the type of node, the number of the node and the number of a terminal inside the node through which the terminating line passes. The CLI, the type of node, the number of the node and the number of the terminal are then used to update routing data in the database.